Question

We looking for distance

Answer 1

240 m

Explanation:

Figure is attached.

The distance the particle travels is the area under the v-t graph over the time interval from 0 min to 4 min. The reason you can't just multiply velocity by time is that the velocity is changing at a constant rate over the given time interval (the line is going upward--the particls is speeding up).

What's the area under the graph?

The red outline forms a trapezoid. The area of a trapezoid is
`A=(1)/(2)h(b_1+b_2)` where the b's are the lengths of the two parallel base and h is the height (the distance between the bases).

Reading the graph carefully (notice the scales!)...

`A=(1)/(2)(4)(30+90)=(2)(120)=240 \text{m}`